In an office information environment, due to the widespread use of computer, software, and network, it became possible to accelerate and share information processing. Fundamentally, digitization of information is excellent in terms of storage, accumulation, retrieval, and so on of information, however, a paper medium is superior in terms of display (particularly viewability) and transfer of information. Therefore, the fact is that as digitization of information is proceeding, the amount of papers used is increasing. On the other hand, reduction of energy consumption typified by CO2 emission is an urgent need in various fields. If a paper medium which is used for temporary display or transfer of information can be recycled, a great contribution can be made to the reduction of energy consumption.
As a color material for recycling a paper medium, a decolorizable color material is conventionally known.
For example, it is proposed that a color is easily developed and erased by heating using a reversible heat-sensitive recording medium. However, since a color developable composition is allowed to exist in a recording medium, the proposal has a disadvantage that a common paper medium cannot be used. Further, it is proposed that, for example, an erasable toner is produced by a pulverization method. However, since a plurality of components such as a color developable agent, a color developing agent, and a decolorizing agent are handled in a solid phase, the proposal has a disadvantage that color developing and erasing reactions are neither prompt nor sufficient.
When a toner is prepared using an erasable color material as described above, the toner has problems that it takes time to erase the color material and a remaining unerased portion is getting noticeable as the number of erasing operations increases.